The present invention relates to an organism identification system, and more particularly to an organism identification system that can identify whether or not a fingerprint image input object is a living body's finger, by utilizing organic information in a fingerprint image input operation. The present invention also relates to an organism identification method.
Conventionally, personal collation has been performed by extracting the feature amount of an input fingerprint image and then comparing it with the feature amount of a fingerprint previously stored. Fingerprints, being information peculiar to a personal, can be processed using digital data with improved resolution to execute personal collation with very high precision.
However, the personal collation by fingerprints may bring the risk that the security is broken by a replica with the same rough surface as that of a genuine fingerprint. In order to avoid such a risk, the conventional way has been carried out by identifying whether or not a fingerprint image input object corresponds to a human's (living body's) finger and then judging that the object is a counterfeit, in spite of the collation result of a fingerprint, if it is identified that the object is not a living body's finger. In order to ensure the security, it is important to identify whether or not a fingerprint image input object corresponds to a living body's finger. Various techniques have conventionally proposed to maintain the security.
JP-A-241680/1992, for example, discloses a security technique. According to this technique, a fingerprint image input object placed on a fingerprint sensor is heated or vibrated at the time of inputting fingerprint data. Then, if there is a response such as "strongly press the fingerprint sensor", "speak", or "press down the key" within a predetermined time, it is judged that the object corresponds to a living body's finger. If there is no response within a predetermined time, it is judged that the object is a replica.
Moreover, JP-A-187430/1994, for example, discloses the technique of identifying whether or not an object is a living body's finger by measuring pulses and blood pressures by a pressure sensor. The pressure sensor is disposed in an image input section on which a finger is rested at a fingerprint collation time. This prior art also discloses the technique of identifying whether or not an object is a living body's finger by detecting infrared rays radiated from a finger by means of an infrared-rays sensor.
However, the above-mentioned prior arts have the following disadvantages.
According to the technique disclosed in JP-A-241680/1992, an illegal person trying to use a replica may act to a response such as "strongly press the fingerprint sensor" or "speak". Moreover, because an illegal person can sense stimulation such as vibrations given to a replica, the replica can be easily recognized erroneously as a living body's finger. That is, when an illegal person senses stimulation such as vibrations given to a replica, the replica can be recognized easily and erroneously as a living body by strongly depressing the fingerprint sensor or uttering a voice.
Moreover, according to the art disclosed in JP-A-187430/1994, the pressure sensor produces a simple signal. Hence, when a pressure is applied to the pressure sensor by using a replica placed on the image input section, the pressure sensor can produce signals (corresponding to pulses or blood pressures) by which the replica is erroneously recognized as a living body's finger. Moreover, in infrared rays sensing technique, a replica can be erroneously recognized as a living body's finger by merely fitting an infrared-ray radiating device with the replica.
JP-A-233556/1989 discloses the art for first identifying a person with a static pattern such as fingerprint, voice pattern, or password number, and then, if passed, providing inquires from a third party to the person, and identifying the person based on responses, electrocardiograms, or brain waves. However, this publication does not disclose the art of automatically identifying whether or not a fingerprint image input object is a living body is identified, at the time of inputting a fingerprint.